gxbb: Initial port of Amlogic Meson S905 (GXBB)

The Amlogic Meson S905 is a SoC with a quad core Arm Cortex-A53 running
at 1.5Ghz. It also contains a Cortex-M3 used as SCP.

This port is a minimal implementation of BL31 capable of booting
mainline U-Boot and Linux:

- Partial SCPI support.
- Basic PSCI support (CPU_ON, SYSTEM_RESET, SYSTEM_OFF).
- GICv2 driver set up.
- Basic SIP services (read efuse data, enable/disable JTAG).

This port has been tested in an ODROID-C2.

Change-Id: Ia4bc82d7aca42a69d6b118b947279f82b3f6c6da
Tested-by: Amit Singh Tomar <amittomer25@gmail.com>
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/plat/meson/gxbb/include/plat_macros.S b/plat/meson/gxbb/include/plat_macros.S
new file mode 100644
index 0000000..948b5f9
--- /dev/null
+++ b/plat/meson/gxbb/include/plat_macros.S
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef PLAT_MACROS_S
+#define PLAT_MACROS_S
+
+#include <gicv2.h>
+#include <platform_def.h>
+
+.section .rodata.gic_reg_name, "aS"
+
+gicc_regs:
+	.asciz "gicc_hppir", "gicc_ahppir", "gicc_ctlr", ""
+gicd_pend_reg:
+	.asciz "gicd_ispendr regs (Offsets 0x200 - 0x278)\n Offset:\t\t\tvalue\n"
+newline:
+	.asciz "\n"
+spacer:
+	.asciz ":\t\t0x"
+
+	/* ---------------------------------------------
+	 * The below required platform porting macro
+	 * prints out relevant GIC and CCI registers
+	 * whenever an unhandled exception is taken in
+	 * BL31.
+	 * Clobbers: x0 - x10, x16, x17, sp
+	 * ---------------------------------------------
+	 */
+	.macro plat_crash_print_regs
+
+	/* GICC registers */
+
+	mov_imm	x17, GXBB_GICC_BASE
+
+	adr	x6, gicc_regs
+	ldr	w8, [x17, #GICC_HPPIR]
+	ldr	w9, [x17, #GICC_AHPPIR]
+	ldr	w10, [x17, #GICC_CTLR]
+	bl	str_in_crash_buf_print
+
+	/* GICD registers */
+
+	mov_imm	x16, GXBB_GICD_BASE
+
+	add	x7, x16, #GICD_ISPENDR
+	adr	x4, gicd_pend_reg
+	bl	asm_print_str
+
+gicd_ispendr_loop:
+	sub	x4, x7, x16
+	cmp	x4, #0x280
+	b.eq	exit_print_gic_regs
+	bl	asm_print_hex
+
+	adr	x4, spacer
+	bl	asm_print_str
+
+	ldr	x4, [x7], #8
+	bl	asm_print_hex
+
+	adr	x4, newline
+	bl	asm_print_str
+	b	gicd_ispendr_loop
+exit_print_gic_regs:
+
+	.endm
+
+#endif /* PLAT_MACROS_S */